140 THE PHARYNX AND NASOPHARYNX Salivary gland sarcoidosis may involve both parotid glands to cause enlargement of the glands and depression of salivary secretion. Diagnosis is made by serological tests for sarcoidosis or by needle biopsy. There is no specific treatment, and as the gland involvement is part of a generalized sarcoidosis the management should be in the hands of a chest physician. Sjogren syndrome (Mikulicz syndrome) is a chronic non-specific inflam- matory reaction producing cellular infiltration of the parenchyma of all the salivary glands. It is usually associated with chronic rheumatic disease. There is initially a generalized enlargement of the salivary glands, but this decreases as a result of the progressive atrophy produced by the disease. The condition is characterized by a progressive and distressing dryness of the mouth, often complicated by a superficial infection of the buccal and pharyngeal mucosa. There is also dryness of the eyes from reduced secretion of tears. There is no specific therapy. Some stimulation of salivary secretion may be obtained by sucking sour sweets of the acid-drop variety. Frequent mouth washes and attention to oral hygiene are important. SALIVARY TUMOURS Salivary gland tumours are not common. Over 80 per cent of salivary tumours are found in the parotid gland (Fig. 57), and 70 per cent of these are of the non-malignant variety. The minor salivary glands are the most frequent site of malignant tumours. Pleomorphic Adenoma (Mixed Salivary Tumour) This is very firm on palpation, and may grow from the substance or the surface of the gland. It is a benign tumour, but may recur after incomplete removal. It usually occurs between the ages of 20 and 40. PATHOLOGY. The tumour is firm, lobulated and encapsulated. Histo- logically the growth is found not to be confined within its capsule, and it is these extensions which tend to recur after removal. The tumour consists of epithelial cells in a hyaline stroma. SYMPTOMS. The swelling is painless, and is usually situated above the angle of the mandible. It is smooth, firm and slow-growing, and the main complaint is of unsightliness, while in males it produces some difficulty with shaving. Malignant Tumours. The most common site for these is the minor salivary glands. They may be found on the mucous membrane covering the hard palate, the base of the tongue or the posterior pharyngeal wall, and they are occasionally met with in the maxillary sinus. The tumours do not metastasize readily, but are locally invasive and may spread to the regional lymph nodes. Rarely they spread along nerve sheaths into the cranial cavity. Muco-epidermoid tumours are uncommon. They consist of epidermoid and mucus-secreting cells. Although classified as malignant the prognosis is reasonably good. Adenoid cystic carcinoma (cylindroma) is a rare tumour and is more usually found in the salivary tissue of the hard palate than in the salivary glands. It is malignant and locally invasive, and may metastasize, but the spread is very slow. Aamc-cell tumours are uncommon malignant growths of the parotid gland whidb occur mainly in females.